Typically, the principle of a water softener is to soften water by substituting Na+ ion for Ca+ ion and Mg2+ ion contained in hard water. The typical softener includes essentially a water softening tank containing ion exchange resins of special highly polymerized compound, and a regenerating tank in which is filled with regenerating substance of ion exchange resins such as salt, etc., for regenerating Na+ ion when dissolved in water.
As shown in a block piping laying diagram of FIG. 1, a conventional typical cold/hot water softener includes a cold regenerating tank 2a, a cold water softening tank 4a connected to the cold regenerating tank, a hot regenerating tank 2b, a hot water softening tank 4b connected to the hot regenerating tank, and a plurality of valves V1, V2, V3, V4, V5, V6. The cold/hot water softening tanks 4a, 4b usually contain an ion exchange resin containing Na+ ion, and salt is filled in each of cold/hot regenerating tanks 2a, 2b only when regenerating.
Thus, upon using soft water, cold raw water low than normal temperature is supplied through the empty cold regenerating tank 2a into the cold water softening tank 4a, and the resulted cold soft water is discharged outside while hot raw water high than normal temperature is supplied through the empty hot regenerating tank 2b into the hot water softening tank 4b, and the resulted hot soft water is discharged outside.
In addition, the existing cold/hot water softener is provided with a plurality of valves in order to control inflow and outflow of raw water and soft water. First and second valves V1, V2 are provided with front ends of cold/hot regenerating tanks 2a, 2b, respectively, for regulating on/off of supply of cold/hot raw water. Third and fourth valves V3, V4 are provided with rear ends of cold/hot water softening tanks 4a, 4b, respectively, for regulating on/off of discharge of cold/hot soft water.
Thus, a user can use water as desired by opening first and second valves V1, V2 and controlling third and fourth valves V3, V4 suitably. Then, the third and fourth valves V3, V4 can be exchanged with typical water links.
Meanwhile, if a water softener is used for a long time, Na+ ion contained in ion exchange resins will be exhausted. Thus, for regenerating Na+ ion, each of the cold/hot regenerating tanks 2a, 2b are filled with salt. Then, the cold/hot regenerating tanks 2a, 2b can be opened with typical stoppers provided therein and have fifth and sixth valves V5, V6 for discharging remaining raw water contained therein.
In order to regenerate ion exchange resins, the first to fourth valves V1, V2, V3, V4 are all closed, the fifth and sixth valves V5, V6 are opened, the remaining raw water contained therein is discharged, and then, salt is filled into each of the cold/hot regenerating tanks 2a, 2b. Thereafter, the first and second valves V1, V2 are opened, raw water is supplied to the cold/hot regenerating tanks 2a, 2b, and the regenerating water in which Na+ ion is dissolved is flowed into each of the cold/hot water softening tanks 4a, 4b, respectively. Accordingly, the ion exchange resins can be regenerated.
Thereafter, the third and fourth valves V3, V4 are opened, components contained salt are all eliminated, and then the regeneration is completed. Accordingly, soft water can be normally used.
However, the above-mentioned conventional cold/hot water softeners had several defects. Firstly, it was difficult to determine regeneration time of ion exchange resins contained in each of the cold/hot water softening tanks 4a, 4b, and thus, the determination thereof entirely depended on the feeling of a user. Consequently, the performance and length of life of ion exchange resins were considerably reduced due to the unnecessarily frequent regenerations or rare regeneration.
Secondly, as described above, because the procedures of regeneration of ion exchange resins was complicated too much in the conventional cold/hot water softeners, a long time of work was required even in the skilled person. In particular, because all of the procedures of regeneration should be operated directly by hand of a user every time, this caused a drawback with a very troublesome work.
Thirdly, because the plurality of valves V1, V2, V3, V4, V5, V6 were included for using the cold/hot water softener, the structure thereof was complicated, failures and malfunction are likely to be caused, and costs of production thereof was expensive.